With the advent of broadcast digital radio based on the in-band on-channel (IBOC) standard developed by iBiquity® Digital Corporation and promulgated by the Federal Communications Commission (FCC), broadcast stations previously capable of only analog transmissions are seeking cost-effective solutions to providing digital broadcasts. Conventional transmitter development has not yet yielded a cost-effective, high-efficiency solution that allows analog and digital signals to be combined and amplified using a stand-alone high power transmitter. In addition, it is understood that many broadcasters would prefer to continue to use previously acquired, operational analog transmitter systems to the extent possible, adding digital subsystems as separate—and less costly—entities. Although there are a number of previously known approaches to effect high power signal combination, these approaches have relatively high power loss, and thus incur increased operating costs. Drawbacks such as these have been deemed to make conventional methods for obtaining IBOC capability unacceptable to many in industry.
Therefore, there has been a long-standing need in the community for systems and methods that can efficiently combine digital and analog signals, and can provide a cost-effective approach to obtaining IBOC transmissions.